java 如何在 Android 中使用自定义正则表达式验证 EditText 输入？
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How to validate EditText input with a custom regex in Android?
提问by topacoBoy
I am new to android development and also regular expression. I am able to retrieve inputs from user through the EditText and check if it's empty and later display the error message if it is empty but I am not sure on how to check with a custom regex. Here's my code :
我是 android 开发的新手，也是正则表达式。我能够通过 EditText 从用户检索输入并检查它是否为空，如果为空则稍后显示错误消息，但我不确定如何使用自定义正则表达式进行检查。这是我的代码：
myInput = (EditText) findViewById(R.id.myInput);
String myInput_Input_a = String.valueOf(myInput.getText());
//replace if input contains whiteSpace
String myInput_Input = myInput_Input_a.replace(" ","");
if (myInput_Input.length()==0 || myInput_Input== null ){
myInput.setError("Something is Missing! ");
}else{//Input into databsae}
So, im expecting the user to input a 5 character long string where the first 2 letters must be numbers and the last 3 characters must be characters. So how can i implement it people ?
所以，我希望用户输入一个 5 个字符长的字符串，其中前 2 个字母必须是数字，最后 3 个字符必须是字符。那么我怎样才能实现它呢？
回答by Mattias Isegran Bergander
General pattern to check input against a regular expression:
根据正则表达式检查输入的一般模式：
String regexp = "\d{2}\D{3}"; //your regexp here
if (myInput_Input_a.matches(regexp)) {
//It's valid
}
The above actual regular expression assumes you actually mean 2 numbers/digits (same thing) and 3 non-digits. Adjust accordingly.
上面的实际正则表达式假设您实际上是指 2 个数字/数字（相同的东西）和 3 个非数字。相应调整。
Variations on the regexp:
正则表达式的变化：
"\d{2}[a-zA-Z]{3}"; //makes sure the last three are constrained to a-z (allowing both upper and lower case)
"\d{2}[a-z]{3}"; //makes sure the last three are constrained to a-z (allowing only lower case)
"\d{2}[a-z???A-Z???]{3}"; //makes sure the last three are constrained to a-z and some other non US-ASCII characters (allowing both upper and lower case)
"\d{2}\p{IsAlphabetic}{3}" //last three can be any (unicode) alphabetic character not just in US-ASCII
